FXUS63 KMQT 080517 AAC
AFDMQT
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MARQUETTE MI
1217 AM EST TUE DEC 8 2009
UPDATED FOR 06Z TAF AVIATION DISCUSSION
.UPDATE...ISSUED AT 1040 PM EST
GOING ADVY FOR ONTONAGON/HOUGHTON COUNTIES APPEARS ON TRACK
OVERNIGHT. WITH KMQT RADAR SHOWING OCCASIONAL RETURNS OVER PORTIONS
OF NRN ONTONAGON COUNTY AND CNTRL/NRN PORTIONS OF HOUGHTON
COUNTY...LES IS LIKELY MDT TO OCCASIONALLY HVY IN THAT AREA.
CONVERGENCE FOCUSED BY LAND BREEZES SHOULD CONTINUE TO MAINTAIN
HEAVIER SNOW SHOWERS IN THAT AREA THRU THE NIGHT. EXPECT AN
ADDITIONAL 2 TO 6 INCHES OF SNOW THERE. KDLH RADAR SHOWS AN LES BAND
(PROBABLY HVY SNOW) ALONG LAND BREEZE CONVERGENCE STREAMING INTO THE
AREA AROUND THE PORCUPINE MTNS. THAT WILL BE ANOTHER AREA FAVORED
FOR SNOW ACCUMULATIONS OVERNIGHT.
&&
.SYNOPSIS...ISSUED AT 430 PM
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WSW FLOW ALF OVER
THE UPR GREAT LAKES BTWN POSITIVELY TILTED UPR TROF STRETCHING FM
JUST W OF HUDSON BAY INTO THE NRN ROCKIES AND RDGING NEAR FL.
SHRTWV/ASSOCIATED SFC LO EMBEDDED WITHIN THIS FLOW IS MOVING THRU
THE LOWER GRT LKS WITH AREAS OF ACCOMPANYING -SN TO THE S OF THE
FA...WHICH IS DOMINATED BY CHILLY LGT NNW FLOW TO THE E OF ARCTIC HI
PRES IN THE NRN PLAINS. AIRMASS OVER THE UPR GRT LKS IS SEASONABLY
CHILLY...BUT MUCH COLDER LURKS TO THE NW. 12Z H85 TEMPS RANGE FM
-11C AT GRB TO -18C AT INL AND -22C AT YQD. INL RAOB IS QUITE FVRBL
FOR LES WITH INVRN BASE NR H8...INVRN BASE TEMP -21C...AND SUB INVRN
LYR RELATIVELY MOIST WITH TEMPS FVRBL FOR DENDRITIC SN GROWTH. WITH
COLD AIR FLOWING OVER THE RELATIVELY WARM LK WATERS...NMRS LES ARE
IMPACTING AREAS OVEF THE NCNTRL BTWN MQT-P53 AND OUT OVER THE W NEAR
IWD WHERE LLVL CNVGC BTWN LAND BREEZES OFF SE ONTARIO AND THE UPR
MIDWEST HAVE ENHANCED LLVL CNVGC WITH THE PREVAILING NNW SYNOPTIC
SCALE FLOW. MQT 88D SHOWS POCKETS OF HIER REFLECTIVITY AOA 28DBZ
WITHIN THE MASS OF SHSN IMPACTING THE NCNTRL. FARTHER TO THE W...
POWERFUL SHRTWV IS MOVING ONSHORE IN CA. CLD LEAF IN ADVANCE OF THIS
SYS IS SPREADING INTO THE CNTRL PLAINS.
&&
.SHORT TERM DISCUSSION /TNGT AND TUE/...ISSUED AT 430 PM
MAIN FCST CONCERNS IN THIS PD ARE LES TRENDS/AMOUNTS TNGT INTO TUE.
FOCUS FOR LATER ON TUE SHIFTS TO HOW QUICKLY SYNOPTIC SN WL SPREAD
IN FM THE SW IN ADVANCE OF SHRTWV NOW CRASHING ONSHORE IN CA.
TNGT...LITTLE WL BE GOING IN ON THE SYNOPTIC SCALE WITH SLOW HGT
RISES/LARGER SCALE QVECTOR DVGC CONTRIBUTING TO SLOWLY RISING MSLP/
SINKING INVRN BASE TO 4K FT MSL. MODELS IN GOOD AGREEMENT SHOWING
H925 FLOW BACKING FM NNW TO WNW LATE TDAY TO 12Z TUE AS CENTER OF
HIEST MSLP BLDS OVER NW WI. WITH BACKING FLOW...LES IN MQT COUNTY
SHOULD WEAKEN QUICKLY TOWARD 00Z. GIVEN RADAR TRENDS SHOWING BAND
SHIFTING OUT OF MQT COUNTY CLOSE TO FCST ISSUANCE...DECIDED TO CANX
GOING ADVY THAT WAS IN EFFECT UNTIL 01Z. ALTHOUGH GOGEBIC COUNTY WL
LIKELY HANG ON TO LES A BIT LONGER...BACKING FLOW/WEAKENING LLVL
CNVGC EVEN WITH NOCTURNAL LAND BREEZE SHOULD TEND TO DIMINISH
ACTIVITY THERE THIS EVNG IN LINE WITH GOING 01Z EXPIRATION TIME OF
ADVY. CONCERN WITH NEED TO EXTEND HEADLINE FOR ALGER COUNTY AND
PERHAPS POST ADVYS FOR ONTONAGON/HOUGHTON COUNTIES AS WELL AS NRN
SCHOOLCRAFT/LUCE COUNTIES. LES CHART SUGS 3-6 INCHES OF SN WL
ACCUMULATE IN 12HRS FOR EXPECTED CONDITIONS...BUT HIER RES LOCAL
MODELS SUG SHIFTING WINDS WL LIKELY LIMIT PERSISTENT CNVGC IN AREAS
E OF MQT. H925 CNVGC SEEMS MORE FOCUSED WITH DVLPG LAND BREEZE FOR A
LONGER TIME OVER THE W FM CMX TO ONTONAGON AND THE PORCUPINE
MTNS...SO OPTED TO GO WITH LES ADVYS FOR ONTONAGON/NRN HOUGHTON
COUNTIES THRU 12Z TUE GIVEN FVRBL SN GROWTH PARAMETERS/LES CHART
NUMBERS. EXPECT THE LOWEST MIN TEMPS TNGT OVER THE INTERIOR W HALF
WITH LTL LK MODERATION IN BACKING LARGER SCALE FLOW/LAND BREEZE.
CONSIDERING OBSVD CHILL IN THE NRN PLAINS...TENDED TOWARD THE LO END
OF MOS GUIDANCE FOR MIN TEMPS IN THESE AREAS WITH JUST SOME HIER CLD
MOVING IN LATER.
WITH LGT WINDS/MORE ACYC FLOW...EXPECT ONGOING HEAVIER LES BANDS TO
DEGENERATE LATE TNGT AND TUE MRNG. OTRW...HI CLD OVC WL BEGIN TO
THICKEN WITH INCRSG ISENTROPIC ASCENT SHOWN ON THE 280-290K SFCS
(H8-6) IN ADVANCE OF SHRTWV LIFTING NE INTO THE CNTRL PLAINS.
BROUGHT IN -SN DURING THE AFTN S TO N...BUT KEPT THE E DRY WITH NO
POTENTIAL FOR LK MOISTENING. MAINTAINED HIER POPS OVER THE FAR
SCNTRL WHERE GFS SHOWS SHARPER H7 FGEN WITH POTENTIAL FOR LK
ENHANCED SN GIVEN ELY FLOW/H85 TEMPS ARND -11C OVER THE RELATIVELY
WARM WATERS OF NRN LK MI AS INDICATED BY LOCAL WRF-ARW RUN.
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THERE WAS ENOUGH AGREEMENT WITH THE AVAILABLE MODELS...AND
SURROUNDING FORECAST OFFICES TO WARRANT AN UPGRADE TO THE ONGOING
WINTER STORM WATCH.
CONCERNED THAT WINDS MAY BE HIGH ENOUGH FOR A BORDERLINE BLIZZARD
WARNING ACROSS THE KEWEENAW PENINSULA...AND FOR MARQUETTE AND ALGER
COUNTIES FROM ROUGHLY 12Z TO 18Z WEDNESDAY. COPPER HARBOR MAY
EXPERIENCE REDUCED VISIBILITY LASTING THROUGH THE AFTERNOON AND
EARLY EVENING HOURS WEDNESDAY. AT THIS TIME...HAVE CONTINUED WITH
THE IDEA OF BLOWING SNOW...AND WINDS JUST UNDER BLIZZARD
CONDITIONS...BUT I WOULD NOT BE SURPRISED IF AN UPGRADE IS NEEDED
FOR KEWEENAW...AND POSSIBLY MARQUETTE AND ALGER COUNTIES AS WELL.
DID SOME MINOR TWEAKING TO THE INCOMING SWATH OF PRECIPITATION
TUESDAY AFTERNOON/EVENING...WHICH RESULTED IN SLOWING DOWN THE ONSET
OF THE HIGHER PRECIPITATION AND RESULTANT WINTER STORM WARNING FOR
NORTHER SCHOOLCRAFT...ALGER...AND LUCE COUNTIES UNTIL 06Z WEDNESDAY.
STORM TOTAL SNOW ACCUMULATIONS BETWEEN 10 AND 18 INCHES ARE FORECAST
BETWEEN 00Z WEDNESDAY AND 06Z THURSDAY. SEE THE ZFP/WSW/GRIDS FOR
SPECIFICS.
LAKE EFFECT SNOW SHOWERS WILL CONTINUE BEYOND THE TIME OF THE
EXPIRED WARNINGS...AND MAY WARRANT LAKE EFFECT SNOW SHOWER
ADVISORIES FOR THE KEWEENAW...AND POSSIBLY EASTERN ALGER AND
NORTHERN LUCE COUNTIES AFTER 06Z THURSDAY. WE WILL LOOK INTO THIS
MORE AS THE WEDNESDAY SYSTEM WINDS DOWN...TO KEEP FOR DOUBLE OR IN
SOME CASES TRIPLE HEADLINES.
SPEAKING OF MODEL CONSISTENCY...850MB TEMPERATURES LOOK LIKE
THIS...-7 TO -11C AT 12Z WEDNESDAY...WITH THE GFS AND ECMWF BEING
PRETTY CONSISTENT. THE UKMET WAS A LITTLE COOLER...RANGING FROM -10
TO -15C. STILL PLENTY COLD FOR LAKE ENHANCEMENT...ALBEIT BRIEF
WEDNESDAY MORNING NEAR LAKE MICHIGAN...AND MORE PERSISTENT
NORTHEASTERLY...TO NORTHWESTERLY FLOW OFF OF LAKE SUPERIOR DURING
THE DAY WEDNESDAY INTO WEDNESDAY NIGHT.
JUST 24 HOURS LATER AT 12Z THURSDAY...THE ECMWF WOULD COOL THE 850MB
TEMPERATURES FROM -17 TO -22C...AND SLIGHTLY COOLER OFF THE GFS
WHICH CAME IN WITH -19 TO -24C. WE ARE STILL ANTICIPATING ONE OF THE
COLDEST MORNINGS OF THE SEASON SO FAR...WITH BELOW NORMAL
TEMPERATURES LIKELY INLAND ALONG THE WISCONSIN BORDER. AT 12Z
FRIDAY ECMWF -19 TO -22C...WITH THE GFS -20 TO -24C. THIS IS WHERE
MODELS BEGIN TO DIVERGE ON THE TEMPERATURE FORECAST. WINDS WILL
BECOME MORE WSW FRIDAY EVENING. DID NOT GO DIRECTLY WITH THE HPC
GUIDANCE FOR SATURDAY MORNING. WAA WILL BE COMING IN...WITH 12Z
SATURDAY 850MB TEMPERATURES HOVERING NEAR -17C OFF THE GFS...WITH A
MUCH WARMER -8C OFF THE ECMWF. ATTEMPTED TO STAY WITH THE COOLER
SIDE OF AVAILABLE MODEL GUIDANCE...WHICH DID NOT CHANGE THE ONGOING
FORECAST TOO MUCH...WHICH WAS A GOOD BLEND OF THE PREFERRED 12Z GFS
AND 00Z ECMWF FOR THE MOST PART. THE DISCREPANCIES ON THIS EXTENDED
PORTION OF THE FORECAST PERIOD WERE MODERATE...NOT TOO BAD.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
AT KCMX...LAND BREEZES WILL LIKELY CONTINUE TO FOCUS CONVERGENCE AND
HEAVIER LAKE EFFECT SHSN INTO THE KCMX VCNTY THRU THE NIGHT. EXPECT
CONDITIONS TO VARY BTWN MVFR AND IFR. AS IS THE NATURE OF LAKE
EFFECT SHSN...CIGS/VIS WILL LIKELY STILL BE MORE VARIABLE THAN
REFLECTED IN THIS FCST AS BANDS TRANSIT THE AREA. POTENTIAL FOR A
MORE WELL DEVELOPED SNOW BAND IS POSSIBLE DURING THE MORNING HRS
ALONG A FOCUSED LAND BREEZE CONVERGENCE ZONE. IFR CONDITIONS SHOULD
PREVAIL...BUT NOT OUT OF THE QUESTION THAT SOME PERIODS OF LIFR WILL
OCCUR. WEAK HIGH PRES RIDGING WILL SHIFT ACROSS THE AREA LATER IN
THE MORNING/EARLY AFTN...THEN WINDS WILL BECOME ERLY AS LOW PRES
BEGINS STRENGTHENING OVER THE SRN PLAINS. SHOULD SEE -SHSN BECOME
DISORGANIZED DURING THIS TIME...ALLOWING VIS TO IMPROVE TO VFR WHILE
CIGS REMAIN MVFR. EXPECT DETERIORATING CONDITIONS DURING THE EVENING
AS RAPIDLY DEEPENING LOW PRES MOVES NE TOWARD THE GREAT LAKES...
SPREADING SNOW INTO THE AREA.
AT KSAW...LIGHT DOWNSLOPING WRLY WINDS OVERNIGHT WILL ALLOW VFR
CONDITIONS TO DOMINATE THRU THE MORNING. VFR CONDITIONS SHOULD THEN
LINGER THRU THE AFTN UNDER INCREASING/THICKENING MID/HIGH CLOUDS
AHEAD OF STRENGTHENING LOW PRES OVER THE SRN PLAINS. EXPECT
DETERIORATING CONDITIONS IN THE EVENING AS RAPIDLY DEEPENING LOW
PRES MOVES NE TOWARD THE GREAT LAKES...SPREADING SNOW INTO THE
AREA.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
OPTED TO BEGIN GALE WATCH A BIT EARLIER TUE NGT GIVEN QUICKER APRCH
OF DEEP SFC LO PRES AND SOME TERRAIN ENHANCEMENT WITH NE FLOW. GALES
WL PERSIST THRU WED BEFORE STRONGER CYC NE FLOW EXITS TO THE NE WITH
DEPARTING SFC LO PRES. ADDED PLENTY OF FREEZING SPRAY TO THE
FORECAST...AS TEMPERATURES STAY NEAR OR BELOW 20F THROUGH THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO 1 AM
EST /MIDNIGHT CST/ THURSDAY FOR MIZ001>005-009>014-084.
WINTER STORM WARNING FROM 1 AM WEDNESDAY TO 1 AM EST THURSDAY
FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ002-003.
LAKE SUPERIOR...
GALE WATCH FROM LATE TUESDAY NIGHT THROUGH LATE WEDNESDAY NIGHT
FOR LSZ266-267.
GALE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING FOR
LSZ243>245-264-265.
GALE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING FOR
LSZ263.
GALE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON
FOR LSZ162.
LAKE MICHIGAN...
GALE WATCH FROM LATE TUESDAY NIGHT THROUGH LATE WEDNESDAY NIGHT
FOR LMZ221-248-250.
&&
$$
UPDATE...ROLFSON
SYNOPSIS/SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC/KF
